1. Field of the Invention
This invention relates to the automation of certain particular stages of the operation of a hay baler and more particularly to an automatic tying control device for a hay baler able to form large-diameter cylindrical bales.
2. Description of the Prior Art
Balers of the present type which are intended to be hitched to a tractor and connected to the power take-off of the tractor to provide the movement of the various elements of the baler including a bale-forming chamber. The hay is fed inside the chamber from a collector that takes up the row from the ground. The row thus introduced into the chamber for forming the cylindrical bale, is gradually rolled up on itself, the bale being formed being subjected to a rotating movement around its axis by inward tightening of a loop formed in a multiplicity of belts passing over several tension rollers some of which have shafts which can be moved as the diameter of the bale being formed increases. Springs act on some of these tension rollers so as to exert, on the belts which surround the bale, a sufficient pressure to make bales of suitable density.
When the bale of hay has reached the desired diameter, it is tied by means of a tie consisting generally of twine which can be introduced by a guiding device in front of the intake opening in the hay baler. The free end of the tie is then grasped by the hay fold and the tie is wound around the bale under the action of the rotation of this bale between the belts which hold it. The baler contains on its back wall a door whose opening makes possible the ejection of the bale after the typing operation. To distribute appropriately the windings of the tie along the axial length of the cylindrical bale, the device for guiding the tie is made to be moved in a back and forth movement along the entire width of the baler.
The movement of this guiding device can be done manually by the operator by pulling on a cable and returning it to the position of the guiding device under the action of a return spring.
There have also been described devices that make it possible to provide the back and forth movement in a semiautomatic manner, for example, in European patent application No. 0046 427 and in French patent application 2,397,144.
Until now, the various operations which follow the formation of the bale inside the baler have not been the object of complete automation and therefore, each time a certain number of manual interventions have been by the operator. Consequently, there are, in particular, irregularities in the tying of the resulting bales and a notable increase in the operating waiting times after the formation of each bale to allow the operation of tying and ejecting the tied bale.